What were you doing at nine last Sunday morning?
I was helping my mom do the cooking at six yesterday evening.
2. 由when / while引导的时间状语从句
She was walking down the street when the UFO landed.
While the girl was shopping, the alien got out.
bathroom, bedroom, kitchen, buy, land, got, shirt, while, expensive, around, strange, follow, kid, cut, climb, jump, shout, ride, cat, ran, anywhere, met, happen, accident, plane, hear, modern, kill, murder, bright, playground, bell, ring, tell, close, silence, meaning, become, earth, hero, fly
barber, scared, recent, destroy, flight, amazing
UFO, alien, terrorist, tragedy
get out, take off, run away, come in, hear about, take place, as ... as ...